Dump-type lifting device for emptying containers



Dec. 24, 1968 NAAB 3,417,888

DUMP-TYPE LIFTING DEVICE FOR EMPTYING CONTAINERS Filed May 12, 1967 Inventor JA/(OB M445 ATTORNEYS United States Patent DUMP-TYPE LIFTING DEVICE FOR EMPTYING CONTAINERS Jakob Naab, Schillerstr. 17, Laubenheim (Rhine), Germany Filed May 12, 1967, Ser. No. 638,002 Claims priority, application Germany, May 13, 1966, Z 12,218 11 Claims. (Cl. 214-303) ABSTRACT OF THE DISCLOSURE The dump-type lifting device disclosed herein for emptying containers comprises a container support carriage having upper and lower rollers which are advanced along guideways by actuation of a hydraulically operated cylinder to first raise the carriage and then tilt it to dump the contents of the container. The guideways have sloping surfaces extending at an acute angle with vertical guide track sections and being engageable with the lower carriage rollers to cam the lower end of the carriage rearwardly, thus tilting it in a dumping direction and increasing torque arm along which the cylinder acts to swing the carriage to its final dumping position.

Field of invention This invention relates to a dumping device for emptying containers, especially garbage containers, into a collector tank.

Background There are various types of container dumping machines. One type is characterized by having the container support lift truck or carriage guided on a swivel arm (see Swiss Patent No. 286,395, for example) or by having the upper part of the lift truck guide rails in the form of a swivel arm or swivel frame (see Austrian Patent No. 181,561, for example). Another type of lift-dump apparatus is characterized by having a container lift truck or carriage which is equipped with upper and lower pairs of running elements, such as rollers, for displacement along side-by-side, laterally spaced apart guide rails. This invention pertains to the latter type of dumping apparatus.

In the latter type of dumping apparatus, it is necessary that the lower rollers of the lift truck leave the fixed guide rails in order to tilt the container to a dumping position and then to direct the lower rollers to re-enter the fixed guide rails or guideways during the return movement. Reference is made to German Patents 655,879 and 867,222 for comparison. .This type of guidance for the dump-type lift trucks requires a smooth transition from the lifting movement to the dumping movement and a shockless re-entry of the lower running elements or rollers into the guide rails. Past attempts to achieve this desired action include the provision of a locking device located at the upper end of the guide rails for the upper running elements of the lift truck (see German Patent No. 655,879) or the provision of an arch-shaped shifting guide on the upper running elements (see German Patent No. 867,222). Finally, the attempt has also been made to eliminate the foregoing disadvantages by controlling the speed of the operating device (see German Patent No. 1,026,685).

All the foregoing measures are more or less satisfactory in the case of dump-type lifting devices having a cable line type of operation. However, they are altogether unsatisfactory in the case of such dump-type lifting device where a dump-type lifting cylinder tilts the dump-type lift truck at the end of the guide track and lifts it along said guide track (see French Patent No. 953,674). With these prior devices, the lift truck must be moved into its final lifting position with a thrust, in order to impart the dumping or tilting movement to the truck. However, the dump-type lifting cylinder of these prior devices, because of its small angle of attack on the lift truck, is not in a position at the end of the return swing to absorb the thrust from the return swing of the lift truck.

Object and summary Therefore, this invention contemplates and has as its major object a novel dump-type lifting arrangement which operates shocklessly and, consequently, with less noise and less wear and tear than prior devices. The construction and the method of operation of the dump-type lifting arrangement of this invention are relatively free of trouble and safe even when fouled.

The foregoing object is achieved by running the lower lift carriage rollers along guide rails which each extend along an oblique or inclined line near their upper ends. The lower lift carriage rollers are adapted to advance over these obliquely arranged or inclined rail portions during the last part of the lifting movement. In this manner, the swiveling or tilting movement of the lift carriage will be introduced prior to the end of the lifting action through the effect of the lift cylinder and through the movement of the lower running elements or rollers along the oblique rail portions. As a result, the lifting movement becomes smooth and the transition to the dumping movement is shock-free. At the end of the return swing of the lift carriage for returning the container to its original upright position, the lower running elements or rollers of the lift carriage will engage the oblique or inclined rail portions. As a result, the extent of the movement of the return swing will be transformed into pulse or vectorial components under the effect of the lower running elements and of the oblique portion of the guide track. One component lies essentially opposite to the direction of effectiveness of the lifting cylinder, and, as a result, can be absorbed by the lift cylinder. Thus, there will be an essentially shockless transition from the return swing or pivotal movement to the lowering movement.

According to this invention, it is particularly advantageous that the upper ends of the guide rails be pivotally mounted about an axis which is coaxial with the swing or pivot axis of a cover plate for the collector tank. The lower regions of the guide rails are attached to the rear wall of the collector tank by means of at least one axially resilient holding or mounting member. As a result of this construction, the guide rails themselves are movable resiliently, to wit, swingingly, within a certain limit, by reason of the axial resiliency of the holding elements in relation to the wall of the collector tank. These resilient mounting or holding elements absorb and buffer the thrust components which lie transversely with respect to the direction of effectiveness of the lift cylinder. The transverse thrust component is developed when the lower running elements of the lift carriage move up onto the slope of the inclined rail portions and also when the lower running elements of the carriage re-engage the inclined rail portions at the end of reverse swinging movement returning the container to its upright position.

The transmissions of shocks from the lift cylinder t the wall of the container can then be avoided altogether, whenever the lift cylinder is swingably mounted at the lower ends of the guide rails, by means of a cross bolt which is attached to the two guide rails. The resilient or elastic mounting of the guide rail and lift cylinder assembly on the wall of the collector tank also offers an additional advantage in that the path of the force need not be guided via the resilient mounting elements.

Advantageously, the lift cylinder may be of the known type having two telescoping parts. In such a case, the extension and retraction of the operative telescoping part of the cylinder is preferably correlated with the movement of the lift carriage in such a manner that the lower running elements of the carriage are still lying at the upper end portion of the slope on the inclined rail portions when the operative cylinder element is fully extended. This correlation provides a particularly soft and safe cushioning of the lift carriage and the emptied container when the lower running elements of the lift carriage re-engage the upper end of the sloped rail portions on the return swing. At the same time, the critical transition in the development of force or in the braking effect transmitted between the telescoping elements of the lift cylinder will be utilized to achieve a shockless, noiseless, and wear-free operation of the device at the time of the transition from the return swinging movement to the lowering movement of the lift carriage.

Further objects of this invention will appear as the description proceeds in connection with the appended claims and annexed drawings wherein:

FIGURE 1 is a side elevation of a dump-type lifting device according to a preferred embodiment of this invention and showing an attached garbage can in its upright starting position;

FIGURE 2 is similar to FIGURE 1 and illustrates the parts positioned where the can is lifted but not yet tilted to its dumping position;

FIGURE 3 shows the position of parts with the can in its final tilted position for dumping the contents into the collector;

FIGURE 4 is a rear view of the device shown in FIG- URE 3; and

FIGURE 5 is a section taken substantially along lines VV of FIGURE 4.

In the example shown, the dumptype lift device of this invention is employed for emptying garbage containers into a garbage collecting truck. A pour-in guide device is shown to comprise a guide housing 2 and a front cover plate 3. Housing 2 is mounted on the rear wall 1 of the garbage collecting truck. Plate 3 is mounted on housing 2 for swinging movement about the horizontal axis 4 and is swingable into the housing when the garbage can 9 is raised and tilted to discharge its contents.

The dump-type lift device of this invention comprises two side-by-side, laterally spaced apart guide rails 5 which are secured to rear wall 1 in a manner to be described in detail later on. A lift carriage 6 forming a part of the dump-type lift device is provided with conventional raising hooks 7 and an abutment plate 8 for supporting garbage can 9. To lift and tilt carriage 6 for dumping the contents of can 9, a dump-type lift cylinder 10 has been provided.

Guide rails 5 each comprise three guide sections, namely an upper section 5a, in which upper guide rollers 11 of carriage 6 run essentially encased, a lower section 512, which together with its rear surface forms an open guide track for lower rollers 12 of carriage 6, and an intermediate section 5c, which is bent forwardly and downwardly and which forms an inclined or sloped surface 5d over which lower rollers 12 must move during the last .part of the lift movement. Each of the guide rails 5 is of one piece, with its sections 511, 5b, and 5c integrally joined together. Each rail 5 is formed in such a manner that the roller engaging guide surfaces on sections 5a and 5b are fiat, parallel and vertically aligned. Rollers 11 engage only the guide surfaces on Section 5a, and rollers 12 engage only the guide surfaces on sections 5b and 50. Section 50 joins the under end of section 5a to the lower end of section 512. The distance between the upper guide rollers 11 and the lower guide rollers 12 on carriage 6 corresponds to the maximum height of lift which must be executed by the carriage. This distance is about equal to the length of the guide track formed in the upper section 5a of each guide rail 5, and, if need be, it can be slightly larger, but not smaller than this guide track in the upper section 5a. Each guide rail 5 is provided at its upper end with aligned, lateral pins 13 which are inserted into the hinge of front plate 3. For this purpose, the front plate is recessed in its lower middle part and is provided with receiving bores for the pins 13, in order to keep these pins 13 coaxial in relation to the swing axis 4 of front plate 3. At the upper ends of guide rails 5, a range spacer 14 is inserted between the two rails so that pins 13 are held in the receiving bores of front plate 3. Secured at the lower end of guide rails 5 is a cross bolt or pin 15 which serves for swingably mounted an extensible, telescopic, hydraulic cylinder 10. Guide rails 5 are joined together by spacer 14 and pin 15 to form a stable, rigid guide frame for carriage 6, said frame being swingably mounted about pins 13. At the lower end of this guide frame is an elastic or resilient support element comprising a composite rubber-metal part 16 which is secured to the rear side of the guide frame and to rear wall 1 of the collector bin. Part 16, which is resiliently compressible and expandable in its axial direction, permits limited swinging movement of the guide frame, which is formed by guide rails 5, relative to rear wall 1 of the collector bin. This swinging movement of the guide frame is buffered in both directions by part 16.

Cylinder 10 is provided with a piston rod 17 terminating in an eye 18 which is pivotally connected to carriage 6. The lower cylinder end is pivotally mounted on bolt 15. The delivery and exhaust of fluid pressure respectively to and from cylinder 10 can be accomplished through an axial bore, bolt 15 and another bore in the front wall of the lift cylinder.

To buffer the lift movement at the end of the lift, spacer 14 may be provided with a resilient buffer 20. The upper ends 21 of guide rails 5 are preferably formed in such a manner that the upper running elements 11 of carriage 6 in the final position of the lift assume a coaxial position relative to the swing axis 4 of front plate 3. Thus, carriage 6 and the attached garbage can 9 swing coaxially in relation to front plate 3. Front plate 3 is then swung inward through the effect of cylinder 10 and against the action of a reset device comprising a spring biased connector arm 22. Under the bias exerted by arm 22, plate 3 is swung back as piston rod 17 is retracted. I

The operation of the dump-lift device just described is as follows:

After garbage can 9 has been set up behind the dumptype lift device, fluid pressure is delivered to cylinder 10 by suitable, unshown, selectively operated control devices. At this initial stage the longitudinal axis of cylinder 10, which intersects eye 18, is parallel with or even at a slight negative angle of pitch in relation to guide track sections 5b, 5a. As a result, initial introduction of fluid pressure into cylinder 10 pushes carriage 6 upwardly to vertically lift can 9 through the support connection provided by hooks 7. This lifting movement is continued in a straight line upward until the lower guide rollers 12 run up on the sloping guide track surfaces 5d in the middle region of guide rails 5. As a result, carriage 6 with can 9 will start its dumping or tilting movement under the combined effect of this sloping guide track 5d and of cylinder 10. At the same time, the working angle of cylinder 10 on carriage 6 becomes larger. The lifting movement combined with the dumping or tilting movement at the upper part of the guide rails will be concluded when carriage 6 is raised into its upper end position where it engages buffer 20, in which upper rollers 11 lie coaxially in relation to axis 4. Lower rollers 12, at the same time, lie at the upper end of the sloping guide surface 5d, but preferably still on said sloping guide surface. The extensible first element 10b of cylinder 10, at the same time, will have emerged more or less completely from the cylinder housing 10a. Since cylinder housing 10a is mounted with its lower end secured to guide rails 5, the thrust with which carriage 6 is pressed against buffer 20 will be absorbed by the guide rails 5 themselves.

In the last part of the simultaneous lift and dump movement, the working angle of lift cylinder has been enlarged to an extent that additional fluid pressure applied to lift cylinder 10 will bring about the continued swinging or swiveling movement of carriage 6 until it reaches the final, fully tilted dumping position shown in FIGURE 3. By correlated selection of the magnitude of the slope of the guide 5d and selection of the dimensioning of cylinder 10, the transition to the actual dumping movement is provided either without any noteworthy increase in pressure in cylinder 10 or else with a previously determined pressure increase in the cylinder.

For swinging back and lowering carriage 6 and garbage can 9, the actuating fluid is exhausted from cylinder 10 so that front plate 3 with can 9 and carriage 6 are swung back under the action of connector arm 22, until it reaches the end position of the front plate under displacement of the hydraulic fluid from cylinder 10. The further return swing takes place under the action of the weight of carriage 6 and of the empty garbage can 9, until lower rollers 12 engage the sloping guide track surfaces 5d. At this encounter, the magnitude of the movement or the torque of the return swing is resolved by surface 5d into two components. The more important of these components lies parallel to the line of action of cylinder 10 and consequently is absorbed by the lift cylinder 10. The other component, lying perpendicular with respect to the first-mentioned component, is absorbed (i.e., cushioned) through part 16. Lower rollers 12 will then run down along the sloping guide surfaces 5d and, finally along the lower guide track section 5b which is in alignment with the upper guide track 5a until the lift carriage has returned to its lowermost rest position where it places garbage can 9 down on the ground.

To protect upper guide track section 5a against fouling, it is desirable to laterally cover up guide track section 5a in the profile of the guide rails 5 (see FIGURE 5) so that only a small slit will remain for the shaft axis of the upper rolls 11.

From the foregoing, it is clear that guide track surfaces 50! and lower rollers 12 provide coacting cam and follower elements for swinging the lower end of the carriage and container assembly rearwardly and upwardly in a dumping direction as carriage 6 is being lifted by actuation of cylinder 10. The axis about which carriage 6 is swung as it is being lifted is coaxial with the axes of rollers 11, and this relative swinging motion of carriage 6 swings cylinder 10 in a clockwise direction to progressively increase the torque arm along which the cylinder lift force acts. This is evident from FIGURES 1 and 3 which show the longitudinal axis of cylinder 10 disposed, initially, forwardly of axis 4 and then tilted, owing to the camming action of guide rail surfaces 5d, so that it moves toward an over-center position extending rearwardly of axis 4 (see FIGURE 3).

What is claimed and desired to be secured by Letters Patent is:

1. A dump-type lift apparatus for emptying containers into a walled collector tank comprising a carriage adapted to carry the container and having upper and lower running elements, rail means along which said upper and lower running elements are guided for movement, means supporting said rail means on a wall of said collector tank, a lift cylinder operatively connected to said carriage and being actuatable to lift said carriage upwardly along said rail means and then to swing said carriage at the upper end of said rail means to tilt the container to a dumping position, said apparatus being characterized in that said rail means is provided with inclined surface means sloping at an acute angle relative to the carriage lift path and being engaged by said lower running element as said carriage approaches the upper limit of its lifting movement to swingably urge said carriage in a dumping direction.

2. The dump-type lift apparatus defined in claim 1 wherein said rail means comprises a pair of side-by-side laterally spaced apart guide rails and wherein said means supporting said rail means on said wall comprises pin means pivotally mounting the upper ends of said guide rails on said wall for displacement about a pivot axis extending normal to the carriage lift path, and resilient means joining the lower ends of said guide rails to said wall and being compressible in a direction to allow limited swinging movement of said guide rails about said pivot axis.

3. The dump-type lift apparatus defined in claim 2 comprising a housing mounted on said tank for guiding material dumped from the container and cover plate means disposed at the entrance of said guide housing and being mounted on said pin means for pivotal movement about an axis that is coaxial with said guide rail pivot axis.

4. The dump-type lift apparatus defined in claim 1 wherein said rail means comprises a pair of side-by-sidc, laterally spaced apart guide rails and wherein said cylinder comprises a cylinder housing slidably receiving at least one extensible member pivotally connected to said carriage, said housing being pivotally mounted at its lower end on a cross piece secured to and extending perpendicularly between said guide rails.

5. The dump-type lift apparatus defined in claim 1 wherein said cylinder comprises a housing pivotally mounted on said rail means and at least one extensible member slidably received in said housing and pivotally connected to said carriage, the position of said carriage being correlated with the length by which said member is extendable to locate said lower running element at the upper end of said inclined surface means when said member is fully extended.

6. The dump-type lift apparatus defined in claim 3 wherein means are provided for limiting upward movement of said carriage to a position where the axis about which said carriage is swingable is coaxial with the pivot axis of said plate means.

7. The dump-type lift apparatus defined in claim 1 wherein said rail means is formed with vertically extending first and second aligned guide rail surfaces respectively engaged by said upper and lower running elements, said surface means being disposed at the upper end of said second guide rail surface and being inclined rearwardly and upwardly with respect thereto.

8. The dump-type lift apparatus defined in claim 1 wherein said upper and lower running elements comprise a pair of upper rollers and a pair of lower rollers, and wherein said rail means comprises a pair of parallel, side-by-side guide rails spaced laterally apart for engagement by respective ones of said rollers in each pair, each guide rail having upper and lower parallel vertical sections and an intermediate, inclined section joining adjacent ends of said vertical sections and defining said surface means, and first and second vertically aligned carriage guide surfaces respectively formed on said upper and lower guide rail sections and respectively engaged by said upper and lower pairs of rollers, said surface means defining an extension of said lower guide surface and being inclined upwardly and rearwardly from said second guide rail surface.

9. The dump-type lift apparatus defined in claim 1 comprising buffer means arranged to engage and limit upward displacement of said carriage.

10. The dump-type lift apparatus defined in claim 8 wherein the length of said first guide rail surface is no greater than the distance between the upper pair of rollers and the lower pair of rollers.

11. The dump-type lift apparatus defined in claim 1 wherein said cylinder is pivotally connected to said rail means and wherein the lift force exerted by said cylinder 7 is applied along its longitudinal axis, said cylinder being disposed With its longitudinal axis essentially parallel to the upward path of cal-rage displacement before said lower running element engages said inclined surface means and being progressively tilted at an acute angle with respect to said path as said lower element rides up along said surface means to angularly displace said longitudinal axis toward an over-center position relative to the axis about which said carriage is swingable for dumping the contents of said container.

References Cited UNITED STATES PATENTS 2,860,795 11/1958 Zoller 214-303 3,095,101 6/1963 Zoller 214302 HUGO O. SCHULZ, Primary Examiner. 

